Ford Focus>> Ignition system>> Ignition coil
In the coil of ignition there are two windings: primary winding with smaller number of rounds (100) from a thick copper wire section 0,6 mm2 and secondary — 1000 rounds from a thin copper wire section 0,1 mm2. Both windings clasp the steel lamellar core. Primary winding receives tension from the onboard power supply network of the car, thanks to it there is a magnetic field which crosses a secondary winding. If the control unit interrupts current passing on primary winding, as a result of an induction the secondary winding makes tension over 30 000 Century.